Apparatus for removing marine organisms and the like

ABSTRACT

A simple apparatus for removing deposits such as marine organisms from underwater structures by utilizing natural force such as waves tides, comprises plural floating bodies linked together. The linked floating bodies repeatedly collide with the underwater structure to remove deposits. The linked bodies can be hollow or solid. A protective cover, comprising two cup-like parts, is preferably provided on the outer circumference of each of the linked bodies. The protective cover may have bridge-like projections for enhancing removal of attached matter, and may be surrounded by a socket ring. Freely rotating collars are provided to prevent accumulation of marine organisms and the like on parts of the removal apparatus that do not directly contact the underwater structures.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to an apparatus for effectively removing marine organisms (shells such as oyster, barnacle, mussel and the like, and seaweed), and other materials which have become attached to an underwater structure, by applying a natural force such as wave force, wind force, and tidal force. The structures to which the invention is applicable include, for example, steel pipe pilings, H-shaped pilings, angular pilings, concrete pilings and walls, perpendicular pilings, horizontal rods, diagonal members, legs including legs of a pier, banks, a floating quay, a float bridge, a pontoon supporting an offshore structure such as sea berth, artificial island, or pier, and the sides and bottom of a ship's hull, especially a ship anchored for the purpose of exhibition. The invention is also applicable to the removal of deposits such as sludge and the like which become entangled with, or attached to, an oil fence or shield fence.

[0003] 2. Description of the Prior Art

[0004] In the routine maintenance of an underwater structure such as the piling supporting an offshore structure, or the bottom of the ship, it is conventional practice to remove deposits such as shells, seaweeds, rust, and sludge periodically.

[0005] These deposits enhance corrosion of steel pipe and the irregularity caused by marine organisms firmly attached there to the pipe increases its effective aperture and consequently increases its exposure to the effects of wind and waves. In the case of a bridge or pier having excessive deposits, the action of wind and waves can bring about abnormal vibrations which may cause the formation of cracks and ultimately result in breakage.

[0006] In a concrete structure, another phenomenon has been observed. The sulfur content of the concrete is removed by marine organisms. Hence, although the concrete structure may appear tough, material is gradually lost from its surface. Because of the above-mentioned effects of marine deposits, it is necessary to remove these deposits periodically. At present, the removal operation is primarily carried out manually, by means of a chaplet rod or a wire brush. There is a very large number of offshore structures, and their operation on the sea or other bodies of water is heavily influenced by meteorological phenomena such as currents, wind and waves, including tidal waves. These phenomena bring about many dangerous conditions. Consequently the number of workers is increased, divers are often necessary, the work is unsafe, and the increased time required to carry out deposit removal operations increases the cost of construction and maintenance and increases construction time.

[0007] These unsafe conditions are also encountered in the removal of deposits attached to the hull and bottom of a ship. Moreover, accumulated deposits cause a marked reduction in the speed of a ship. Therefore, at the present time periodic repair and maintenance operations are carried out. for example, deposits are scraped off at a dock.

[0008] Many attempts have been made to reduce the manpower required in marine deposit removal operations. For example, special paints including antifouling agents, or substances which produce toxic ions, have been used to prevent or suppress attachment of marine organisms such as shells and seaweeds, or to kill such organisms. Piling covers have also been used to protect underwater structures.

[0009] Chemicals such as antifouling agents pollute the nearby sea, causing environmental problems, and also pose a hazard to workers. Moreover, as a practical matter, it is impossible to prevent completely the attachment of marine organisms, and therefore periodic removal operations are inevitable.

BRIEF SUMMARY OF THE INVENTION

[0010] Object of the Invention

[0011] This invention was developed to address the above described problems. The apparatus of the invention removes deposits such as marine organisms and the like from the surface of an underwater structure at sea or in brackish water, by contacting the surface of the structure with a structure that is movable, not only vertically but also in various directions as a result of wind and wave forces, including tidal current. The apparatus effectively removes deposits attached to a concrete or steel pipe piling or to the bottom of a ship, by repeated collision. In addition, the invention makes it possible to install a body, which is used for removal of deposits, so that it fits the external shape of concrete and the steel pipe pilings from which the deposits are to be removed.

[0012] As used herein, the term “marine organisms and the like” includes not only organisms such as shells, seaweeds, plankton, and the like, but also organic and inorganic matter such as sludge, sand, gravel, rust, and other materials which may become directly attached to an underwater structure, or indirectly attached to an underwater structure by becoming entangled with, or attached to, other such materials which are themselves directly attached to an underwater structure. The term “marine organisms and the like” includes both aquatic organisms and brackish water organisms. The problem of attachment of marine organisms and the like to underwater structures exists in different environments, including sea water, rivers, lakes, and also brackish waters in which fresh water is blended with seawater. Accordingly the apparatus of this invention is applicable to marine organisms and the like in all these environments.

[0013] My previous invention of a float type apparatus for removing deposits using vertically moving wave forces, tidal forces and the like is described in U.S. Pat. No. 5,894,808, granted Apr. 20, 1999. The invention described therein was found to effect nearly complete removal of deposits of marine organisms such as shells and seaweed attached from concrete and steel pipe piling within several days.

[0014] As a further improvement of the float type, deposit-removal apparatus, I also proposed an apparatus providing for a relatively slow and steady deposit removal action in order to prolong the life of the deposit removal structure. With the improved apparatus, deposits are steadily and completely removed from an entire surface of an area to which marine organisms have become attached, without any deposits remaining. The improvements are described in Japanese Patent Application No. 9-363304 and Japanese Patent Application No. 10-188068.

[0015] As a rule, marine organisms such as shells and seaweed often become attached at a location near the surface of a body of water, either just above and just below the surface. The deposits gradually thicken, becoming entangled with dirt and mud floating on the sea surface. The above-described inventions previously proposed have been found very effective for removal of such deposits.

[0016] The present invention is a further improvement on the above-described inventions. Marine organisms such as shells and seaweed occasionally become attached to an underwater structure and live in a range from the surface of the water to several meters beneath the water surface. To remove these organisms, the above-mentioned patent applications describe a multi-step deposit removal system and another float type deposit removal apparatus providing for the collection of marine organisms and reliquiae that have been removed.

[0017] The object of this invention is to provide a deposit removal apparatus having one or more of the following attributes: the capability of effectively and completely removing deposits such as marine organisms by employment of a simple structure; and safer operation achieved by reduction of the frequency of removal and replacement of the apparatus.

SUMMARY OF THE INVENTION

[0018] The apparatus in accordance with the invention comprises a plurality of link bodies articulably connected together in a series, each link body having an outer surface having an annular portion and an associated protective cover, the annular portion of the outer surface of each link body being surrounded by its associated protective cover.

[0019] The annular portion of each link body is preferably in the form of a circular annulus, and a clearance is provided between the annular portion of each link body and its associated protective cover, so that the protective covers can rotate about the link bodies.

[0020] Each protective cover preferably includes regions engageable with its associated link body when the protective cover moves relative to its associated link body in either direction along the length of the connected series of link bodies.

[0021] In an embodiment of the invention, each protective cover comprises a pair of separable cup-shaped elements having interfitting projections and recesses which snap together to hold the separable, cup-shaped elements together in covering relationship with an associated link element.

[0022] In a preferred version of the invention, at least a part of a circumferential outer face of each protective cover comprises a plurality of bridge-like projections for collision against a surface of the underwater structure.

[0023] Each protective cover is preferably rotatable on its associated link body about an axis extending in the direction of the connected series of link bodies, and elongated bridge-like projections provided on the protective cover for collision against a surface of the underwater structure, extend substantially parallel to the axis of rotation of the protective cover.

[0024] In a preferred embodiment of the invention in which each protective cover comprises a pair of separable cup-shaped elements having interfitting projections and recesses which snap together to hold the separable, cup-shaped elements together have radially extending portions that constitute bridge-like projections for collision against a surface of the underwater structure.

[0025] Each end of a link body preferably has an ear extending therefrom for articulating connection to a next link body. Each such ear has at least one substantially planar face for engagement with a corresponding substantially planar face of an ear of an adjacent link body, and the ears on the opposite ends of each body are disposed so that the planes of the substantially planar faces thereof cross each other.

[0026] The protective cover is preferably made of a resin having a durometer hardness in the range from 75 to 85.

[0027] A socket ring may be provided on the portion of the protective cover surrounding the annular portion of the outer surface of each link body. Preferably, the socket ring has an inner face with recesses receiving and closely fitting bridge-like projections on the outer face of the protective cover and an outer face with a plurality of projections elongated in directions substantially parallel to the axis of rotation of the protective cover.

[0028] When the link bodies are articulably connected together by linking elements, each of at least a plurality of the linking elements is surrounded by a freely rotating collar having a circular shape or an ellipse-like shape in the form of an elongated circle.

[0029] In a version of the apparatus in which first and second removal tools, each comprising a series of articulably connected link bodies, are located one below the other, a flexible link may be provided to connect the first and second removal tools, and at least part of the flexible link is preferably covered by a resin pipe which limits the motion of the linking tool.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030]FIG. 1 is an elevational view of transverse explanatory view of a link body of the removal apparatus of the invention;

[0031]FIG. 2 is an exploded perspective view showing the manner in which two link bodies are connected together, and also showing the manner in which a two-part protective cover is assembled over a link body;

[0032]FIG. 3 is an perspective view illustrating an outlined appearance of the a two stage removal apparatus arranged around a piling;

[0033]FIG. 4 is an exploded perspective view, similar to FIG. 2, but also illustrating a connector for connecting a lower stage of a multiple stage removal apparatus to an adjacent higher stage;

[0034]FIG. 5A is a schematic, bird's-eye view illustrating an example of the removal of marine organisms and the like deposited on the bottom of the ship utilizing the invention;

[0035]FIG. 5B is a vertical section further illustrating the removal operation of FIG. 5A;

[0036]FIG. 6A is a side elevation of a socket ring attachable to the outer circumference of a protective cover in accordance with the invention;

[0037]FIG. 6B is a sectional view of the socket ring;

[0038]FIG. 7A is a sectional view showing a link body having a protective cover and a socket ring installed on the outside of the protective cover;

[0039]FIG. 7B is a schematic end view of the assembly of FIG. 7A, illustrating the transverse relationship between the ears at opposite ends of the link body;

[0040]FIG. 8 is an exploded view of a portion of a removal device in which a freely rotatable collar is installed on the connection between two adjacent link bodies; and

[0041]FIG. 9 is a perspective view of a two stage removal apparatus in accordance with the invention, in which the upper and lower stages are connected together by chains or the like, each chain being covered by a resin pipe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The link body used in the removal apparatus in accordance with the invention can be either solid or hollow, and the link body 1 of FIG. 1 is a hollow body having a somewhat elongated pillow shape. The link body should have a circular cross-section, but can be of various shapes, for example, spherical, or in the shape of a pepo. Preferably, the hollow body is symmetric, except for ears, which, as will be explained later, are used to connect linking bodies to one another and to other components of the removal apparatus.

[0043] The hollow interior 2, designated by a broken line in FIG. 1, is preferably formed by blow molding, but the hollow body may be produced by other methods.

[0044] Because the removal apparatus removes marine organisms attached to an offshore structure or the like while floating on or under the surface of a body of water, a hollow link body has the advantage of greater buoyancy, as compared with a solid body. If the apparatus has insufficient buoyancy, however, auxiliary floats or buoys can be used.

[0045] Ears 3 and 4 are provided on opposite ends of each link body 1 in order to link the individual link bodies together. Individual ears 3 and 4 have flat faces, and are provided with holes 3-1 and 4-1, respectively. A fastener such as bolt is inserted in these holes 3-1 and 4-1 to link adjacent link bodies 1 to one another.

[0046] Adjacent link bodies 1 may be loosely connected to allow an articulating motion. Alternatively, however, by tightening the fastener, the link bodies may be secured together in a specific angular relationship.

[0047] As shown in FIG. 1, the ears 3 and 4 are preferably disposed with their faces respectively in imaginary planes which are transverse, and preferably orthogonal, to each other. The transverse relationship of the ears enables adjacent link bodies to rotate with respect to each other, but prevents alternate link bodies (that is, link bodies connected to opposite ends of a given link body) from rotating in the same direction. If the link bodies are connected together to form a ring, the transverse relationship of the ears on each link body helps maintain the general annular shape of the ring.

[0048] In contrast, if the ears 3 and 4 of each link body were located in the same plane, wave force would tend to deform the ring of link bodies. However, since a ring of link bodies having coplanar ears will bend irregularly over time, even this arrangement is capable of effecting complete removal of attached matter, provided that it is utilized in a long term removal operation.

[0049] The overlapping ears of adjacent link bodies should meet on a plane in which the centerlines of the link bodies lie. Therefore, as shown in FIG. 1, ear 4 is positioned on the link body so that one of its faces is on the center line of the link body. One of the faces of ear 3 is likewise on the center line.

[0050] The main role of the link body is to remove marine organisms and the like by floating on or below the surface of a body of water. A hole (not illustrated) may be provided for introducing water into to the hollow interior 2 of a hollow link body to reduce its buoyancy, so that the removal apparatus, or a part thereof comprising a series of hollow link bodies 1, may be submerged for removal of marine organisms attached to a structure below the surface of the body of water.

[0051] The hole can be made closable, or, in case the removal apparatus is intended for use only in removing operations below the surface, the hole can be kept open.

[0052] The material of the link body may be a hard material so that the link body itself may serve the function of removing marine organisms and the like. However, in order to prevent wear of the link body, a protective cover described later may be used.

[0053] A resin such as polypropylene, polyethylene, nylon or the polyacetal copolymer known as DURACON, manufactured by Polyplastics Co., Ltd. or hard rubber are preferred for use as the material of the link body, whether it be a hollow body or a solid body. However, other materials may also be used provided they exhibit good moldability, capability of use in a floating body, wear resistance, ability to remove deposits such as shells and seaweeds, and avoidance of wear to underwater structures such as the steel pipe, concrete, and the like.

[0054]FIG. 2 shows a protective cover 5 disposed over the outer circumferential face of the link body 1. The inner diameter of the protective cover 5 is somewhat larger than an outer diameter of the link body 1, so that a clearance is provided allowing the cover to rotate on the outer circumference of the link body 1.

[0055] The protective cover 5 comprises two cup-shaped parts 5-1 and 5-2, which can be separated from each other. The parts and have projections 6 and a grooves 7 which mate with each other, holding the cup-shaped parts together by a snap fit. Each cup shaped part has a hole through which an ear of the link body can extend. In the assembly process, hollow parts of two cup-shaped protective cover parts 5-1 and 5-2 are positioned opposite each other and brought together while passing the ears 3 and 4 of the link body 1 through the holes of the respective cup-shaped cover parts.

[0056] The protective cover 5 covers almost the entire link body 1 and is freely rotatable thereon when assembly is completed. Because of the cup-like shape of the two parts of the cover, the cover can rotate on the link body, but is prevented from moving longitudinally on the link body. In operation, the protective cover repeatedly collides directly with marine organisms and the like which have accumulated on the surface of an underwater structure.

[0057] The material of the protective cover 5 can be the same material as that of the link body, vinyl chloride, polypropylene, polyethylene, nylon, polyacetal copolymer, or hard rubber being preferably used. However, other materials can also be used.

[0058] Snap-fitting of the cover parts may be inadequate to keep the parts together under some conditions, for example, rough waters. Therefore, after the cup-shaped protective cover parts 5-1 and 5-2 are snap-fit to each other, they can be welded together permanently to prevent separation.

[0059] After the protective cover 5 is attached to the link body 1, as shown in FIG. 2, a connecting bolt 9 is used to connect adjacent link bodies 1 to one another. In a typical application, a chain-like series of link bodies 1 linked to each other, while floating on the surface of a body of water, is extended around a piling or similar offshore structure, and both ends of the series of link bodies 1 are connected together to form an annulus.

[0060] Thereafter, wave force causes the apparatus to go through unlimited repeated motion, both vertical and otherwise, for effective removal of marine organisms and the like from the structure.

[0061] As shown in FIG. 2, on at least a part of the circumferential face of the protective cover 5, a plurality of bridge-like projections 10 are provided. These bridge-like projections, which preferably extend perpendicular to the direction of rotation of the protective cover 5, collide with the surface of the underwater structure.

[0062] As shown in FIG. 2, some of the bridge-like projections are formed on the outer surfaces of the cover parts between the interengageable projections and grooves, while others are formed in part on the projections and in part in alignment with the grooves. If part and all of the bridge-like projections are aligned with the interengageable projections and grooves the strength of the projections is improved, and the formation of the cover parts is simplified.

[0063] The vertical movement of the floating removal apparatus resulting from wave forces and the like causes the bridge-like projections 10 to collide with the underwater structure, and also causes the protective covers to rotate irregularly around the circumference of the link bodies 1 to carry out effective removal of marine organisms.

[0064] The bridge-like projections 10 are especially effective in the initial removal of marine organisms that have become so firmly attached to the surface of the underwater structure that they are very difficult to remove by hand.

[0065] Needless to say, wear of the bridge-like projections 10 of the protective cover 5 reduces the effectiveness of the removal apparatus. However, even if the bridge-like projections 10 are completely worn away, marine organisms and the like will continue to be removed by the protective cover 5. Moreover, even if the protective cover 5 itself is worn away, the link bodies 1 themselves have the ability to remove marine organisms and the like effectively. Although it is advisable, for more efficient removal, to replace the cover with a new protective cover 5 at the point where the protective cover 5 has become seriously worn, as a rule, at the time of replacement, removal of marine organisms has already been nearly completed.

[0066] A hard protective cover may crack occasionally in use and, the harder the resin is, the shorter its average lifetime is. A higher frequency of replacement results in decrease in efficiency of removal of marine organisms and the like. Therefore, prolonging the life of the protective cover 5 is very important.

[0067] Consequently, particularly where it is important to keep the removal apparatus in service for a long time or where it is otherwise important to prolong its life, it has been found that a soft protective cover is more effective than the hard protective cover. With the objective of long service life in mind, it is preferable to form the cover from a resin having a durometer hardness in the range of approximately 75 to 85 as shown in JIS K7366. Soft vinyl chloride and the like are preferable as cover materials. On the other hand, as shown in FIGS. 6A and 6B a socket ring 30 may be used. A socket ring installed on the outer circumference of the protective cover 5 further prolongs the life of the protective cover while providing for efficient removal of marine organisms and the like.

[0068] The inner face of the socket ring preferably fits onto parts or all of the bridge-like projection 6 on the outer circumferential surface of the protective cover 5. The socket ring 30 is easily attached and can be stably installed. In addition, when required, a resin-based adhesive can be used to achieve a firmer connection between the protective cover 5 and the socket ring 30.

[0069]FIGS. 7A and 7B show examples in which the protective cover 5 is attached to the outer circumference of a hollow link body 1, and a socket ring 30 has been installed on the outer side of the protective cover.

[0070] The socket ring 30 preferably has a plurality of projections 31 formed thereon, each projections 31 extending along the width of the outer circumferential surface of the socket ring in a direction perpendicular to the direction of rotation of the protective cover 5.

[0071] The projections on the socket ring further improve the removal of marine organisms and the like. To reduce wear and prolong the life of the socket ring, it is also preferable that the material of the socket ring 30 be similarly formed of a resin having a durometer hardness in the range of approximately 75 to 85. The entire link body 1, the protective cover 5, and the socket ring 30 can be made from the resin and a weight of these three components together should be about 1.5 kg or less, and preferably 1.2 kg or less, in total. Thus, the weight of 10 link components connected together can be 15 kg or less (excluding the weight of the fasteners, and the weight of 20 link components connected together can be 30 kg or less. The relatively light weight of the equipment makes transportation, assembly, and installation very easy on land, ship, and the sea and also increases the ability of the apparatus to be moved by waves, tidal forces, and wind forces, for further improvement in the effectiveness of the apparatus in removal of marine organisms and the like is further improved. Consequently, the removing apparatus according to the invention is not only more effective in the removal of marine organisms and the like, but is also light in weight and therefore more easily transported and handled.

[0072] In a preferred embodiment of the removal apparatus, as shown in FIGS. 8 and 9, a freely rotatable collar 32 with a circular or elliptical section is installed over the connected ears joining adjacent link bodies.

[0073] Marine organisms do not attach themselves to the portions of the removal apparatus which continuously colliding with an underwater structure. However, marine organisms and the like may occasionally become attached to the parts of the removal apparatus which connect the link bodies together. The accumulated matter may become dense over time, with little distance between the accumulated matter and the parts which contact the underwater structure. When this condition occurs, the irregular motion of the removal apparatus resulting from wave and tidal forces tends to disappear, and the effectiveness of the apparatus in removal of accumulated marine organisms and the like diminishes markedly. The free motion of the collars installed over the connecting parts of the removal apparatus inhibits attachment of marine organisms to the apparatus itself, and prevents the attached marine organisms and the like from smoothing the irregular motion of the removing apparatus. A similar collar can be installed around a resin pipe to be described later, for similarly preventing attachment of marine organisms to the pipe.

[0074] The collar preferably has an ellipse-like, elongated circular shape, so that it is tapered. Contact at the tip thereof effectively inhibits attachment of marine organisms.

[0075]FIG. 3 shows a structure comprising two removal apparatuses, each comprising link bodies connected together to form a ring. The rings are arranged one above the other. FIG. 3 shows an example of a two-layer structure. However, the removal structure can consist of only a single ring floating on the sea surface, or can consist of any desired number of rings in multiple layers.

[0076] In FIG. 3, the position of the upper removal apparatus corresponds to the position of the surface of a body of water. Therefore, the lower ring 12 is positioned under the sea surface.

[0077] In the apparatus of FIG. 3, the structure of the link bodies 1 is similar to the structure illustrated in FIG. 2, each link body having a protective cover. The rings are disposed about a the steel pipe piling 13. In FIG. 3, the size of the rings 11 and 12 relative to the piling 13 is exaggerated for clarity. However, the diameters of the rings should be somewhat larger than the diameter of the piling, because excessively small ring diameters result in increased friction against the marine matter to be removed, and the excess friction reduces the motion of the link bodies 1 and the frequency of the repeated collisions caused by wave forces and the like, resulting in decreased removal efficiency and in some cases failure of the apparatus to work. On the other hand, excessively large ring diameters result in reduced contact between the removal structure with the matter to be removed and consequently removal efficiency drops. Therefore, the diameters of the rings should be adjusted properly, taking into account conditions such as the thickness of the deposits, the diameter of the piling, and the wave height.

[0078] As shown in FIG. 3, the lower ring 12 is suspended under the surface of the body of water by suspension chains or wires 14 connected to the upper ring 11. The link bodies 1 of the lower ring 12 can filled with water if hollow to reduce buoyancy, or solid bodies can be used to limit buoyancy.

[0079] The use of hollow bodies is advantageous because they can be used in two ways: filled with air or other gas for increased buoyancy, and partially or completely filled with water for decreased buoyancy.

[0080] The upper ring 11 is loaded by the weight of the lower ring 12 and the suspension chains or wires. A buoy 15 can be installed on the suspension chain or wire if appropriate. It is preferred that the buoy be a hollow buoy, made of foamed plastics by extrusion molding. However, other kinds of buoys, prepared from other materials and by other methods, can be used.

[0081]FIG. 4 shows the structure of the link body 1 used in the lower ring 12. The structure of the link body 1 is same as that used in the ring 11 except that a connecting bolt 18 is used to link a suspension chain 16 and a suspension plate 17 with the ring 12 at an appropriate position.

[0082] By utilizing a two layer removal apparatus as described above, marine organisms and the like accumulated over a large area of a structure, both on and under the water surface, can be removed.

[0083] Although, not illustrated, a net for collection of marine organisms and the like removed from an underwater structure can be attached underneath rings 11 and 12.

[0084] As described above, in the case where the two stage or multistage removal apparatus is installed, a first stage of the removal apparatus floating on the sea surface moves vigorously under the influence of the waves and wind. It is desirable that the removal apparatus suspended under the first or upper stage also move vigorously. However, in the case where the lower removal apparatus is suspended by a chain or wire 14, the flexibility of the suspension chain or wire inhibits the transfer of the motion of the upper stage to the lower stages, making the motion of the lower stages less effective.

[0085] According to the invention, in order to solve this problem, as shown in FIG. 9, the suspension chain or wire 14 covered by a resin pipe 33. The pipe rigidifies the suspension, and causes the lower stage or stages to move along with the upper stage. Hence, the removing effect of a multiple stage annular removing apparatus can be improved.

[0086] A collar 32 as described above can be disposed around the resin pipe 33 to prevent deposition of marine organisms on the pipe.

[0087]FIGS. 5A and 5B show an example of rapid and effective removal of marine organisms such as shells and seaweed firmly deposited on the bottom of a ship. WL represents the water surface.

[0088] The link bodies 1, which float on the water surface around the hull 20, are linked together like the links of a chain to form two series of link bodies, one series being on the starboard side of the hull, and the other series being on the port side of the hull. One or more chain-linked removal apparatuses 21 are connected to the series of link bodies on both sides of the hull and extend underneath the hull from one series of link bodies to the other.

[0089] A protective cover 5 is disposed on the outer circumferential face of each link body 1. Single-dotted chain lines indicate the arrangement of the series of link bodies 1 and the removal apparatuses 21.

[0090] For the removing apparatus 21 shown in FIG. 5, a series of interconnected link bodies similar to the linked bodies shown in FIG. 3 or FIG. 4 can be used. The link bodies can be solid bodies, or hollow bodies in which air is replaced by water.

[0091] At appropriate positions along the series of link bodies, buoys 19 can be installed to improve buoyancy. Ropes 22 are attached to a bow and a stern, and the lengths of the ropes can be adjusted to control the positioning of the link bodies 1 for optimum repeated collision with the hull.

[0092] In the apparatus according to the invention, the wind, and the waves beating against the hull 20 cause irregular deformation of the series of link bodies 1, and collision of the protective covers thereon with the bottom of the ship. In addition, the removing apparatuses 21, which extend underneath the hull, can repeat the irregular motion and collide with the bottom of the ship for effective removal of marine organisms and the like deposited on the bottom of the ship.

[0093] The link bodies 1 having protective covers 5 are linked to adjacent link bodies 1, and the series of link bodies can be deformed within a limited range around the underwater structure, the limitation of deformation being due to the transverse arrangement of the respective ears on each link body. Therefore, series link bodies 1 do not deform in an unlimited manner, but instead keep their general shape, for example an annular shape. Consequently, ineffective motion of the link bodies 1 is reduced and the removal effect is enhanced.

[0094] The apparatus removes marine organisms and the like by mechanically applying a natural force such as wind force, wave force, and tidal force and not by chemicals and the like. The linking mechanism reduces ineffective motion, and the protective cover is arranged on the outer circumferential surface of the link body to prolong the life of the apparatus and to reduce the frequency of replacement and removal of the apparatus. The apparatus is capable of stable operation for rapid and effective removal of deposits of marine organisms such as shells and seaweed which have become firmly attached to underwater structures such as perpendicular pilings, other underwater structures which extend horizontally and diagonally, and bottoms of ships or the like.

[0095] The protective cover is adapted to the link body structure and is divisible into two parts and thus, easy to attach to the link bodies. In addition, bridge-like projections on the protective cover increase the impact force of the apparatus against marine organisms and the like, and enhance the removal effect.

[0096] In addition, the following advantageous effects are achieved. The apparatus collides repeatedly with deposits existing around the water surface and under the water surface simultaneously to remove them, and is capable of effectively removing such marine organisms as shells and seaweed firmly attached to almost all areas of an underwater structure within a short interval of time. 

What is claimed is:
 1. An apparatus for removing marine organisms and the like from a surface of an underwater structure by floating the apparatus in proximity to said surface and causing the apparatus to collide repeatedly with said surface, comprising a plurality of link bodies articulably connected together in a series, each link body having an outer surface having an annular portion and an associated protective cover, the annular portion of the outer surface of each link body being surrounded by its associated protective cover.
 2. The apparatus for removing marine organisms and the like according to claim 1, wherein the annular portion of each link body is in the form of a circular annulus, and in which a clearance is provided between the annular portion of each link body and its associated protective cover, whereby the protective covers can rotate about the link bodies.
 3. The apparatus for removing marine organisms and the like according to claim 1, wherein the annular portion of each link body is in the form of a circular annulus, and in which a clearance is provided between the annular portion of each link body and its associated protective cover, whereby the protective covers can rotate about the link bodies, and wherein each protective cover includes regions engageable with its associated link body when the protective cover moves relative to its associated link body in either direction along the length of the connected series of link bodies.
 4. The apparatus for removing marine organisms and the like according to claim 1, wherein each protective cover comprises a pair of separable cup-shaped elements having interfitting projections and recesses which snap together to hold the separable, cup-shaped elements together in covering relationship with an associated link element.
 5. The apparatus for removing marine organisms and the like according to claim 1, wherein at least a part of a circumferential outer face of each protective cover comprises a plurality of bridge-like projections for collision against a surface of the underwater structure.
 6. The apparatus for removing marine organisms and the like according to claim 1, wherein each protective cover is rotatable on its associated link body about an axis extending in the direction of the connected series of link bodies, and wherein at least a part of a circumferential outer face of each protective cover comprises a plurality of elongated bridge-like projections for collision against a surface of the underwater structure, the elongated bridge-like projections extending substantially parallel to the axis of rotation of the protective cover.
 7. The apparatus for removing marine organisms and the like according to claim 1 wherein each protective cover comprises a pair of separable cup-shaped elements having interfitting projections and recesses which snap together to hold the separable, cup-shaped elements together in covering relationship with an associated link element, and wherein the projections which snap together with said recesses have radially extending portions that constitute bridge-like projections for collision against a surface of the underwater structure.
 8. The apparatus for removing marine organisms and the like according to claim 1, wherein each of said link bodies has opposite ends, each end having an ear extending therefrom for articulating connection to a next link body in said series, wherein each ear has at least one substantially planar face for engagement with a corresponding substantially planar face of an ear of an adjacent link body, and wherein the ears on the opposite ends of each body are disposed so that the planes of the substantially planar faces thereof cross each other.
 9. The apparatus for removing marine organisms and the like according to claims 1, wherein the protective cover is made of a resin having a durometer hardness in the range from 75 to
 85. 10. The apparatus for removing marine organisms and the like according to claim 1, wherein a socket ring is provided on the portion of the protective cover surrounding said annular portion of the outer surface of each link body.
 11. The apparatus for removing marine organisms and the like according to claim 1, wherein at least a part of a circumferential outer face of each protective cover comprises a plurality of bridge-like projections, wherein a socket ring is provided on said part of the circumferential outer face, and wherein the socket ring has an inner face with recesses receiving and closely fitting said bridge-like projections.
 12. The apparatus for removing marine organisms and the like according to claim 1, wherein each protective cover is rotatable on its associated link body about an axis extending in the direction of the connected series of link bodies, and wherein a socket ring is provided on the portion of the protective cover surrounding said annular portion of the outer surface of each link body, the socket ring having an outer face with a plurality of projections elongated in directions substantially parallel to the axis of rotation of the protective cover.
 13. The apparatus for removing marine organisms and the like according to claim 1, wherein each protective cover is rotatable on its associated link body about an axis extending in the direction of the connected series of link bodies, wherein at least a part of a circumferential outer face of each protective cover comprises a plurality of bridge-like projections, and wherein a socket ring is provided on the portion of the protective cover surrounding said annular portion of the outer surface of each link body, the socket ring having an inner face with recesses receiving and closely fitting said bridge-like projections, and the socket ring also having an outer face having plurality of projections elongated in directions substantially parallel to the axis of rotation of the protective cover.
 14. The apparatus for removing marine organisms and the like according to claim 1, wherein a socket ring is provided on the portion of the protective cover surrounding said annular portion of the outer surface of each link body, and wherein the socket ring is made of a resin having a durometer hardness ranging from 75 to
 85. 15. The apparatus for removing marine organisms and the like according to claim 1, wherein the link bodies are articulably connected together by linking elements and in which each of at least a plurality of said linking elements is surrounded by a freely rotating collar having a circular or elliptical shape.
 16. The apparatus for removing marine organisms and the like according to claim 1, wherein the link bodies are articulably connected together by linking elements and in which each of at least a plurality of said linking elements is surrounded by a freely rotating collar having an ellipse-like, elongated circular shape.
 17. The apparatus for removing marine organisms and the like according to claim 1 wherein said plurality of link bodies constitutes a first removal tool, and including a second removal tool located below the first removal tool, the second removal tool also comprising a second plurality of link bodies articulably connected together in a series, each link body of the second plurality having an outer surface having an annular portion and an associated protective cover, the annular portion of the outer surface of each link body of the second plurality also being surrounded by its associated protective cover, and the apparatus also including a flexible link connecting the first and second removal tools, at least part of the flexible link being covered by a resin pipe which limits the motion of the linking tool. 